Rust preventive compositions containing diamidocarboxylic acids



United States PatentO RUST PREVENTIVE COMPOSITIONS CONTAININGDIAMIDOCARBOXYLIC ACIDS John D. Spivack, Cranston, and Harry Kroll,Warwick,

R. 'L, assignors to Geigy Chemical Corporation, a corpdration ofDelaware N Drawing, Applicatigm'JIllyI2 7, 1953,

Serial N0.370,617

12 Claims. ,(Cl. 252-692) invention relates to-ruist preventive oleaginous compositions;- More articularly theinvcnncii relates to the use ofcertain nitrogenous corrosion or rust inhibitors in compositionscontaining predorifinaritlyafi oleaginousvehicle, and which compositionsmay become contaminated withwater or steam,

The'pfevention of rust formation 'is' particularly important intheprotection of metal surfaces, particularly ferrous surfaces'wheresuclisurfao'esare' to he lubricate'd in the presence of contaminatingmoisture. M ois'ture'may enter lubricating systems 'ofland-land marineturbine-engines; for example, by leakage through steam glands andthrough water-cooled heat exchangers or sn'nplyuby condensation from theatmosphere; The presence of-rust is iniuriousb'ecause"it"causesexcessive wear of g'eiar's and bearing surfaces; and may also clog thehydraulicover: nor system, which las't result"may lead to 'dangerousmperating" speeds. Furthermore, the presence of rust hasbeen shown tomcrease the rate of oxidative' breakdown of the lubricant The preventionof rusting is alsdcssential in the movingpart-s of hydraulic'syst'emsgenerally, such ashydraulic baling'f' machinery, presses; etc. Gtherintportant appli-a'tio'hs "of rust" preventive compounds are inpreservative-oils,'sluslring'oils; flushing oils, etc

A great many materials" have been proposed for pr cvention of rustformation of metal surfaces, however,

relatively few have been applicable iri'pnacticedforthe protection oflubricant systems because most are deleterious to the lubricant, thelubricant systemor are disad= va'ntageous in some other way. lthas beenproposed to add various carboxylic .acid amides to hydrocarbon oilseither tor rust prevention or in order to improve the film-i st nengthandwadhesion towmetals. U. S.P.atent No. meassswmmrpcmm an aoe'toacetylam-ideh'aving an acylre'sidue whi'chis lot a higher fatty acid ornaphthenis: acid, such .as C17H37CONHC2H4NHCOCH2COCH3,formelauerpurpsse; And IL-S. Patent N-fol 2,403 ;293'dis= closes theincorporation of oleic monoamide of ethylene diarfiine or ofpolyethylene polyamines, purportedly a rustpmofirig composition; I It isclaimed in'U. 8'. Patents NO;' ,490;74 1- Of December 6, 1949,and'N0.-2,540;800 of February 6, 1951, (that the lalkenyl succinicanhydride .mrine reaction product" oonfcrsrust' proofing propertieslil'bi'lca't-lllfg'follsl Accordingwto' the; presentinvention, it hasnow been found that" the corrosive efiect of lubricating oils andgreases-(-o1eaginousvehicle) upon bearing surfaces, gears and othermetallic parts "in the presence of water imay be prevented ayincorporation in asaid-oleaginous ve hicle-of a' -smau amsumcra class ofcompounds which are 'di-amidocarboicylic acids and their salts, inwhichai high molecular weight aliphatic acid residue is boundto an amidenitrogen; substituted also by a carbamyl'alkyl group and by acarboxya-lkyl group. Such compounds;- when' used in small amounts inlubricating compositions, it has been determined'ona scientificbasisg-ieifeeti-vely prevent the rusting of metal-suriaces; articularly"those of ferrous metals, upon exposure to water or steam.

2,7 90,180 Patented Apr. so, 1957 2 These additives moreover preventrusting without influencing the lubricant action d sadvantageously.

The rust prevention composition of this invention consists of ni'ajoramounts of an ole'aginous vehicle and a minor" amount of the class ofcompounds diamidocarboxylic acids and their salts having the empiricalformula (CHzMCONRzRi (onumooox whereRi-represents an aliphaticcarboxylic acid residue of CsC24,-or alkyl phosphoryl, alkyl phosphonyl,alkyl sulfonyl, alkyl sulfuryl, wherein the 'alkyl radical has this samenumber of carbon atoms; where n. and m' represent the integersl or 2;where R2 and R3 respectively represent alkyl of aryl groups or H; and Xrepresents H or groups capable of forming salts with the carboxylic acidgroup, such as ammonium or substituted ammonium group's, e. g.- organicamines, and metals, etc.

The higher molecular weight acid in the amide group can be anyof thehigher fatty acids, either saturated or olefinic" unsaturated, of thischain length, such as from ca'pry'lic acid through behenic in thesaturated series. Many of these higher saturated and unsaturated fattyacids occur as glycerides in tats and oils in nature'or as estefs ofmonohydricalcohols in waxes, But higher molecular weight aliphatic acidswithin this general class which do not occur naturally, such ,asthe'mixed carboxylic acids in oxidized liquid or solid hydrocarbons, canbe used. It will be understood that mixed acids can be used of any ofthese-sources, i. e., mixed higher fatty acids, or the synthetic mixedaliphatic acids from hydrocarbon oxidation, or mixtures of each, etc.

The diamidocarboxylic acids-and their salts of the present invention canbe prepared in a number of ways, e. g. as outlined in Equations A, B, orC below.

0 show NH (OHi)mCN NaOH 0 our con-m" l aqueous }CHt)mCOONa lnx 0(crmnoonm .0 (ononooNm he Hi) mo 0 0M WhereM is a metal 0 0'1-15) Alumnita candispersable in the vehicle. If the diamidocarboxylic acid or itssalts are not soluble therein, at least in the percentage added,solubilizers may be added which bring this about; a suitable agentforthis purpose is disclosed subsequently. The term oleaginous vehicle asused in the specification and claims includes mineral lubricating oilsderived from the refinement of petroleum or any of the so-callednon-mineral oils, such as animal, vegetable oils, fats, the syntheticpolyesters of organic acids, polysiloxane, polyalkylene glycols,polyolefins, also the rustproof bases which may be used as the medium ofapplication of rust preventive additive to the metal surface.

Some members of the lubricating oil base will be preferred for specificapplications while other members will be preferred for other technical,industrial applications,.where rust prevention is the objective. For itis obvious that the type of lubricating oil or grease for such surfacesas machine parts, piston rings, machine guns, light arms, gears, turbineengines, and the moving parts of hydraulic baling machinery, or presses,metal drums, etc., will vary greatly.

Some members of this class of compounds, namely of the diamidocarboxylicacid additives, will be preferred for specific industrial applications,while other members will be preferred for other technical or industrialapplications where the aim is to prevent rust formation. As to theselection of the additive, the conditions of use of the finishedlubricant and/or the type of oleaginous vehicle will dictate orinfluence the selection. It can be mentioned that for use in turbinelubrication, the finished lubricant must permit ready separation ofentrained water. It is essential for many reasons, which will not beelaborated upon, that water be easily separable from turbine lubricantsby auxiliary oil purification equipment such as settling tanks, filters,blotter presses, centrifuges, etc.

The amount of corrosion inhibitor incorporated in the finishedlubricating composition may be very small, amounts of the order of0.0125%1%, based on the total finished oil lubricant, being sufiicientto secure metallic corrosion prevention, more particularly where thesurface is ferrous in nature. Greater amounts may be added as dictatedby particular requirements and EXAMPLE I (N-stearoyl)iminodiacetonitrile(36.1 grams) was dispersed in 170 milliliters of water at 65 to 70 C.containing 4.4 grams of sodium hydroxide. The temperature of thereaction mixture was gradually raised to 100 C. and maintained at thistemperature for about 2% hours until substantially 0.1 mole of ammoniagas was evolved and swept out through the apparatus by a stream of Butthey are nitrogen gas. The reaction mixture was thencooled to 20 C. andneutralized with 6 N hydrochloric acid. A precipitate was formed,filtered and washed thoroughly with water. After drying, 40.0 gramsof alight tan powder were obtained. This melted at 134 to 139 C withdecomposition and had a neutralization, value of 390. The neutralizationequivalent Weight for (N- stearoyl) (N-carbamylmethyl)glycine is 398.Recrystallization from an isopropylacetate-methanol mixture yielded pure(N-stearoyl) (N-carbamylmethyl) glycine melting at 148 to 149 C. j

The product described in the example was tested for its rust preventiveproperties by dissolving it in asolvent --2,'7oo,veo v refined andfiltered non-additive turbine grade lubricating mineral oil of 150Saybolt Universal Seconds viscosity at 100 F. and subsequently testingthese oil solutions by the Static Water Drop Corrosion Test describedafter Example H.

EXAMPLE II 31.7 grams of (N-lauroyl)iminodiacetonitrile was dispersed in250 milliliters of water containing 4.4 grams of sodium hydroxide warmedto 60 C. The reaction mixture was stirred and heated at C. for two hoursand twenty-five minutes until substantially 0.1 mole. of evolved ammoniahad been swept out of the reaction mixture by a stream of nitrogen gas.After cooling the reaction mixture to 30 C. it was made acid to pH 2.0with 6 N sulfuric acid. The precipitate which formed was filtered,washed with water and dried to a constant weight of 32.5 grams. Onrecrystallization from ethyl alcohol the purified (N-lauroyl)(N-carbamylmethyl)- glycine melted at 148.5 to 149.5 C. It had aneutralization equivalent weight of 332. The theoretical neutralizationequivalent weight of (N-lauroyl)(N-carbamy1- methyl)glycine is 314.

The respective products described in the example were tested for theirrust preventive properties by dissolving each in a solvent-refined andfiltered non-additive turbinegrade lubricating mineral oil of 150Saybolt Universal Seconds viscosity at F. and subsequently testing theseoil solutions by the Static Water Drop Corrosion Test described above.Briefly, the test consists essentially of observing rusting at F. in thepresence of liquid water in the dimple of a triangular cold-rolled steelspecimen immersed in the test oil. An effective rust preventive oil willprevent rusting for several days while straight mineral oils permitrusting to occur within 2 hours of test.

' solubilization of these diamidocarboxylic acids was effected by theaddition of a solubilization agent which per se'in oil solution hadlittle, if any, rust preventive properties. The agent used was PrimeneJMR, a commercially available primary, aliphatic amine, which has atertiary-alkylamine structure, the tertiary groups having from 18 to 24carbonatoms. It is marketed by Rohm and Haas Company. The results ofthese tests are given in Table I.

Table I.--Rust preventive properties of diamidocarboxylic acids inlubricating oil Wt. Wt. Per- Static Water Additive Example Percent centPri- Drop Corrosion (A) No. (A) (A) mene Test" Time to J MR 1 Rust(Hours) Base Oil None None Less than 16. Stearic Acid" 0. 20 None Do.Primene J MR 1 None 0.20 Do. stgiriifi Acid-d rimene 0.20 0. 20 Lessthan 2. (N -stearoyl) (N-carba- I 0.0125 v 0.0125 More than 200.mylmethyl) glycine. N-lauroyl) (N-carba- II 0.025 0. 025- More than 150.

. mylmethyl) glycine. I

1 "Primene J MR is a mixture of highly branched, aliphatic primaryamines having the tertiary-alkylamine structure in which the primaryamino nitrogen is directly attached to a tertiary carbon atom; it iscomposed principally of amines from eighteen to twenty-four carbon atomsand the predominant portion may be represented by the formula,t-Orr-zrHar-nNHr. It contains about 55-10% non-amine material. It is anon-viscous liquid, colorless to straw colored, insoluble in water anddoes not dissolve water to an appreciable extent. It exhibits solubilityin hydrocarbon solvents and glyceride oils or fats, and in other organicliquids previously referred to under the term "oleaginous vehlcles'f.Additional physical properties are:

Refractive Index, 25 0 Boiling Point (or Range) NeutralizationEquivalent 301. Flash Point (Tag, open cup). 250 F.

oior, Varnish Scale 4-.

It is evident that the rust preventive efiectiveness of answe s?)lubricating oil' solutions of the 'diamidocarboiiylieacids is muchimprovedover the base oil alone or solubilizer' in it. It "is alsoevident that the diamidocarboxylic' acids are qualitatively "superior:in "rust preventive effectiveness than a typical'high'molecular weightfatty acid such as stearic acid.

Having' disclos'cd the natureof 'our invention and the manner in whichit may be practiced, what we claim "and desire to protect by LettersPatent are the following:

1. A rust preventive oleaginous composition adapted for use in the"presence of water, in systems containing metal susceptible of corrosionbyjsai'd :Water, comprising an' oleaginous vehicle and 1adiamidocarboxylic vacid having the following empirical formula:

(CHDnCONH:

(GHQ-IO X where R1 represents an aliphatic carboxylic acid residue ofC8-C24, where n and m each represents integers 1-2, and X representshydrogen and groups capable of forming salts with the carboxylic acidgroup, said diamidocarboxylic acid being present in said oleaginouscomposition in minor amounts, as little as a fraction of 1% to amountsgreater than 1% but in sufiicient quantity to inhibit corrosion of saidmetal to a great degree when compared to the check.

2. A rust-inhibited oil composition adapted for use in the presence ofwater, in systems containing metal susceptible of corrosion by saidwater, comprising a hydrocarbon oil and a diamido carboxylic acid havingthe following empirical formula:

(CHQ'IC ONHa 1N\ (CHzh-C 0 OX where R1 represents an aliphaticcarboxylic acid residue of Cit-C24, where n and m each representsintegers 1-2, and X represents hydrogen and groups capable of formingsalts with the carboxylic acid group, said diamidocarboxylic acid beingpresent in said oil composition in minor amounts, as little as afraction of 1% to amounts greater than 1% but in suflicient quantity toinhibit corrosion of said metal to a great degree when compared to thecheck.

3. A rust preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible of corrosionby said water, comprising an oleaginous vehicle and a diamidocarboxylicacid having :the following empirical formula:

where R1 represents an aliphatic carboxylic acid residue of Ca-C24,where n and m each represents integers 1-2, and X represents hydrogenand groups capable of forming salts with the carboxylic acid group, saiddiamidocarboxylic acid being present in said oleaginous composition inminor amounts, as little as a fraction of 1% to amounts greater than 1%but in sutficient quantity to inhibit corrosion of said metal to a greatdegree when compared to the check, and alkyl primary amines having 18-24carbon atoms in sufficient amount to solubilize said diamidocarboxylicacid, in the oleaginous vehicle, the said alkyl amines being soluble inthe oleaginous vehicle but insoluble in water.

4. A rust preventive oil composition adapted for use in the presence ofwater, in systems containing metal susceptible of corrosion by saidwater, comprising a a 6. hydrocarbon ,o'ilfanda diamidocarboxylicacidhaving the following empirical formula:

(OHsh-CONH! RiN (onmtooox where: R1 represents-an aliphatic carboxylicacid residue of Cs-C24, where n and in each represents integers -2, andX represents hydrogen and groups capable. of form? ing salts with the:carboxylicl acid group, said-diamidocarboxyl'ic acid being spresen tinsaid oil composition in minor amounts, aslit'tle as a fraction of 1%to amounts greater than 1% but in suificient quantity toinhibitcorrosion oftsaid metal to .a great degree when compared to thecheck, and alkyl primary amines having 18-24 carbon atoms in suflicientamount to solubilize said diamidocarboxylic acid, in the hydrocarbonoil, the said alkyl amines being soluble in hydrocarbon oil butinsoluble in water.

5. A rust-preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible of corrosionby said water, comprising an oleaginous vehicle and a minor amount of(N- stearoyl) (N-carbamylmethyl) glycine, as little as a fraction of 1%to amounts greater than 1% but in sufficient quantity to inhibit thecorrosion of said metal to a great degree when compared with the check.

6. A rust-preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible of corrosionby said water, comprising an oleaginous vehicle and a minor amount of(N- lauroyl) (N-carbamylmethyl) glycine, as little as a fraction of 1%to amounts greater than 1% but in sufficient quantity to inhibit thecorrosion of said metal to a great degree when compared with the check.

7. A rust-preventive oil composition adapted for use in the presence ofWater, in systems containing metal susceptible of corrosion by saidwater, comprising a mineral oil and a minor amount of (N-stearoyl) (N-carbamylmethyl) glycine, as little as a fraction of 1% to amountsgreater than 1%, but in sufiicient quantity to inhibit the corrosion ofsaid metal to a great degree when compared with the check.

8. A rust-preventive composition adapted for use in the presence ofwater, in systems containing metal susceptible of corrosion by saidwater, comprising a mineral oil, a minor amount of (N-lauroyl)(N-carbamylmethyl) glycine, as little as a fraction of 1% to amountsgreater than 1%, but in sufficient quantity to inhibit the corrosion ofsaid metal to a great degree when compared with the check.

9. A rust preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible to corrosionby said water, comprising an oleaginous vehicle, a minor amount of(N-stearoyl) (N-oarb amylmethyl) glycine, as little as a fraction of 1%to amounts greater than 1% but in a sufiicient quantity to inhibitcorrosion of said metal to a great degree as compared with the check,and alkyl primary amines having 18-24 carbon atoms in sufficient amountto solubilize said acyl (N-carbamylmethyl) glycine, in the oleaginousvehicle, the said alkyl amines being soluble in the oleaginous vehiclebut insoluble in Water.

10. A rust preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible to corrosionby said water, comprising an oleaginous vehicle, a minor amount of(N-launoyl) (N-oarbamylmethyl) glycine, as little as a fraction of 1% toam'ounts greater than 1% but in a sufiicient quantity to inhibitcorrosion of said metal to a great degree as compared with the check,and alkyl primary amines having 18-24 carbon atoms in sufiicient amountto s'olu bilize said acyl (N-carbamylmethyl) glycine, in the oleaginousvehicle, the said alkyl amines being soluble in the oleaginous vehiclebut insoluble in water,

...7 11. -A rust preventive oil composition adapted for use in thepresence of water, in systems containing metal susceptibl'e to corrosionby said water, comprising a mineral oil, a minor amount of (N-stearoyl)(N-carbamylmethyl) glycine, as little as a fraction of 1% to amountsgreater than 1% but in a suificient quantity to inhibit corrosion ofsaid metal toa great degree as compared with the check, and alkylprimary amines having 18-24 carbon atoms in sufl'icient amount tosolubilize said acyl (N-carb amyl- 'methyl) glycine, in the mineral oil,the said alkyl amines being soluble in the mineral oil but insoluble inwater. I 12. A rust preventive oil composition adapted for use in thepresence of water, in systems containing metal susceptible to oorrosionby said water, comprising a mineral .Oil, a minor amount of (N-lauroyl)(N-carbamylmethyl) References Cited in the file ofthis patent UNITEDSTATES PATENTS CaIdwell Feb. 22, 1949 White et 1 Sept. 25, 1951 I it i;

1. A RUST PREVENTIVE OLEAGINOUS COMPOSITION ADAPTED FOR USE IN THEPRESENCE OF WATER, IN SYSTEMS CONTAINING METAL SUSCEPTIBLE OF CORROSIONBY SAID WATER, COMPRISING AN OLEAGINOUS VEHICLE AND A DIAMIDOCARBOXYLICACID HAVING THE FOLLOWING EMPIRICAL FORMULA: